The present invention relates to a living body inspection apparatus for detecting movement of regions of a living body using a coil which generates magnetism.
A Parkinson's disease is a cerebropathy having a new structure caused by chronic degeneration of cranial nerve. Though it is a cerebropathy, no characteristic symptoms are found in a blood test or observation with diagnostic imaging. It is therefore an actual situation that the severity of Parkinson's disease is decided and a dosage is adjusted according to clinical symptoms (trembling, tension of muscles, abnormality of posture, etc.) and complaint of the patient.
To quantitatively decide the severity of Parkinson's disease, a method of tapping the keyboard of a computer has been studied so far and this method allows ON/OFF movement of fingers to be evaluated simply (e.g., see Movement Disorder, vol. 15, No. 1, 2000, pp. 36-47).
In addition to the method of keyboard tapping, a technique of measuring timing of pressing buttons is reported and an apparatus for pressing buttons is simple and allows ON/OFF movement of fingers to be evaluated simply as in the case of using a keyboard (e.g., see U.S. Pat. No. 6,416,485).
On the other hand, as a method of evaluating movement of fingers in an analog form, a method using an optoelectronic camera system (system for detecting movement of fingers from a camera image) is reported (e.g., see Movement Disorder, vol. 12, No. 5, 1997, pp. 665-676).
As an input apparatus for a sign language, a method of detecting movement of fingers by exciting a primary winding and detecting movement of the positions of a magnetic response member and a secondary winding is reported (e.g., see JP-A-2003-15810). The technique described in JP-A-2003-15810 allows bending and stretching of fingers to be detected. According to the technique described in JP-A-2003-15810, an oscillation coil is placed at each finger tip, a detection coil is placed on the palm of a hand, AC currents of different frequencies are passed through the respective oscillation coils and a frequency detection circuit detects an induced electromotive force obtained from the detection coil on the palm of the hand to find which finger touches the palm of the hand.
In the field of a metal detection apparatus, a method of detecting a metal object moving between a fixed excitation circuit and a detection coil is reported (e.g., see JP-A-5-5784). According to the method described in JP-A-5-5784, an amount of variation due to an eddy current is detected by a detection circuit and detected through a low pass filter.
To quantitatively decide the severity of Parkinson's disease, it is necessary to observe coordinated movement that two or more regions of a living body (two fingers or two lips, etc.) try to move simultaneously. The keyboard tapping method described in Movement Disorder, vol. 15, No. 1, 2000, pp. 36-47 and the method of pressing buttons described in U.S. Pat. No. 6,416,485 can only obtain digital ON/OFF information and cannot detect the degree of stretching of fingers. The methods described in Movement Disorder, vol. 15, No. 1, 2000, pp. 36-47 and U.S. Pat. No. 6,416,485 cannot sufficiently decide the stiffness of movement of fingers which is characteristic of Parkinson's disease.
The method described in Movement Disorder, vol. 12, No. 5, 1997, pp. 665-676 allows collection of analog data about the degree of stretching of fingers but since it detects movement of fingers from images, data processing is complicated and takes much detection time. On top of this, it also results in a large system which is costly.
According to the technique described in JP-A-2003-15810, the information obtained by the frequency detection circuit is binary information of ON and OFF indicating whether the palm of the hand is touched or not and cannot sufficiently decide stiffness of movement of fingers which is characteristic of Parkinson's disease.
The method described in JP-A-5-5784 is principally intended to detect an amount of change of movement of metal and acquires no information on movement of a living body.
In order to solve the above described problems, it is an object of the present invention to provide a living body inspection apparatus for detecting movement of regions of a living body in a simple structure capable of continuously detecting signals caused by movement of two or more regions of the living body (coordinated movement).